WizardBlack Posted July 23, 2008 Share Posted July 23, 2008 I've perused about every thread in this section (awesome info, BTW) and didn't notice any mentions of the effect of removing the drip rails. They are (IMHO) something that the car looks better without, so I was planning on removing them when I get into a bit of panel repair. Any theories? I'd think that some section of them must cause a bit of drag, but I know some people mentioned a-pillar width not being ideal, etc. Quote Link to comment Share on other sites More sharing options...
260DET Posted July 23, 2008 Share Posted July 23, 2008 One comparision that is relevant is between the S30 and S130 in that area, remembering that the S130 had a lot of aero effort put into it and the S30 none. S130 also still looks fairly modern around there, the S30 ancient. Compare the rear quarter windows too. Quote Link to comment Share on other sites More sharing options...
Tombarace14 Posted July 23, 2008 Share Posted July 23, 2008 The advice given to us during the testing was if anything, the A pillars needed to be wider to make air flow around the side and not over it. You could do this by, removing the trim and welding a piece to connect the edge of the drip rail and the A pillar. This would help some but still might not be wide enough. Only testing it could tell. Quote Link to comment Share on other sites More sharing options...
bjhines Posted July 23, 2008 Share Posted July 23, 2008 The drip rails are an important part of the upper structure of the car. I would seriously reconsider "shaving" them unless you plan on a full cage for your car. I was seriously considering an Aero windshield that sat on top of the original mounting position and allowed the windshield to extend past the drip rails. Quote Link to comment Share on other sites More sharing options...
heavy85 Posted July 24, 2008 Share Posted July 24, 2008 I noticed something interesting on the way to an autox this past Saturday. There was a very light mist and I only have RainX - no wipers. I watched the pattern how the tiny (and I mean tiny) drops that formed traveled across the windshield. In the middle the air goes straight up but from there out it's sort of a sunburst pattern where the air goes from straight up in the center to horizontal towards the sides. Since the windshield bubbles out in the middle I guess this shouldn't be surprising but I thought was interesting. So do you want the air to go around the windshield or over it? I assume this depends somewhat on if you are looking for downforce (more flow over the rear wing) or more streamlined. Any thoughts? Cameron Quote Link to comment Share on other sites More sharing options...
bjhines Posted July 24, 2008 Share Posted July 24, 2008 The more air going over the car the better. It is only countered by the fact that the area of highest velocity is the area of lowest pressure. You dont want to create any more lift. The idea behind the extended-width windshield is the get the air past the open window that is required for most track duty. A wider lip pushes the air further out and extendeds the distance rearward that it comes back into the window's plane. Flushing the quarter glass and moving the front edge of the quarter glass forward would improve the airflow along the sides of the car. The existence of the drip rail may actually improve performance in this area on this car. Most cars spill the air from the top to the sides. The form-over-function design of the S-30 body allows uncontrolled spillover from the sides and top surfaces. Hell, there is even spillover between the bottom and sides. The spillover changes from the front to the rear of the body. It diverges at the windshield in front and then converges back over the rear deck. The vortex generators at the rear edge of the roof seemed to reduce spillover on the rear hatch. They also made the various spoilers slightly more effective. Perhaps some VGs could be applied to the hood to produce similar results. The problem to overcome is the stalled mass of air in front of the windshield. That might disrupt any effect the vortexes might have. The stalled air has the benefit of acting like an extended/raked windshield. There is always a tradeoff without a completely new design. Quote Link to comment Share on other sites More sharing options...
WizardBlack Posted July 24, 2008 Author Share Posted July 24, 2008 Thanks for the responses. Just to respond, my car already has a 6-point in it, so the structure side (shouldn't) be a concern. I plan to extend it out to the front strut towers and some other stuff eventually. How about installing aerodynamic "wings" that just run the length of the A-pillars and are made out of adjustable aluminum brackets and lexan or plexiglass? I've seen lots of similar things for big touring motorcycles like the Honda Goldwing, etc. I swear I have seen some of this stuff on the Factory Five Racing Type-65 Coupe (which is a very similar body style; designed by the same guy?). Quote Link to comment Share on other sites More sharing options...
WizardBlack Posted July 24, 2008 Author Share Posted July 24, 2008 I can't get the factory five owner's forum to come up right now to link some customized stuff, but here's the link to the car: http://www.factoryfive.com/coupehome.html Very similar. You may be able to pick up a few bits of interesting design features from it. Note the quarter panels scoop air in. Likewise, there are two scoops where the ends of our cowl panel would be. This car looks to have a similar windshield bulge and width design. Likewise, go to the customer gallery. Watch the top picture; it rotates from one to the next. Pay attention to the shot of the blue one and it's A-Pillars. You will see the lexan/plexi pieces they installed to affect the airflow. I believe the 3000GT has similar pieces at the rear quarter glass / hatch area to get the air to flow from the sides of the car back over the hatch. The 06/07 STi uses a similar piece at the back end of the roof to get air directed down over the trunk. Here are some direct links (if they work): http://www.factoryfive.com/table/ffrkits/coupe/coupestories/images/1436.jpg Another of the cowl scoops and the bottom mounting of the A-Pillar aero guides: http://www.factoryfive.com/table/ffrkits/coupe/coupestories/images/1445.jpg The specific image I was mentioning first; frontal shot: http://www.factoryfive.com/table/ffrkits/coupe/coupestories/images/1471.jpg I should think this would get the effect you are looking for, no? Quote Link to comment Share on other sites More sharing options...
WizardBlack Posted July 24, 2008 Author Share Posted July 24, 2008 On the topic of the windshield trim causing drag; why not cut it flush with the glass? Particularly if your car isn't "rain worthy"? Quote Link to comment Share on other sites More sharing options...
260DET Posted July 25, 2008 Share Posted July 25, 2008 What is the purpose of those rear quarter scoops? http://www.factoryfive.com/table/ffrkits/coupe/coupestories/images/1471.jpg Because they look like they would have no aero benefit and would create a lot of drag. Quote Link to comment Share on other sites More sharing options...
m4xwellmurd3r Posted July 25, 2008 Share Posted July 25, 2008 they could be for cooling of some sort. I get the idea with the A pillar attachements. I think with some VG's in front of the windshield combined with the a pillar rails, it would reduce the amount of spillage over the sides of the body. in that case, the drip rails could actually function to reduce spillage from the roof as well. Quote Link to comment Share on other sites More sharing options...
rudypoochris Posted July 25, 2008 Share Posted July 25, 2008 How are the drip rails structural? Trying to understand this one here. Thanks! Quote Link to comment Share on other sites More sharing options...
WizardBlack Posted July 25, 2008 Author Share Posted July 25, 2008 What is the purpose of those rear quarter scoops? http://www.factoryfive.com/table/ffrkits/coupe/coupestories/images/1471.jpg Because they look like they would have no aero benefit and would create a lot of drag. That is what I was wondering. It'd make more sense from a cockpit ventilation standpoint to vent it out. (shrug) Quote Link to comment Share on other sites More sharing options...
260DET Posted July 25, 2008 Share Posted July 25, 2008 That is what I was wondering. It'd make more sense from a cockpit ventilation standpoint to vent it out. (shrug) Yeh, there is no radiator or other cooling element back there? Only proper reason I can think of. The A pillar shrouds/deflectors may be effective, not sure about some of those scoops though. Quote Link to comment Share on other sites More sharing options...
Challenger Posted July 25, 2008 Share Posted July 25, 2008 The drip rails are just the roof skin and the side panels crimped together to make an edge. Their structural because it gives the edges of the roof rigidity. Quote Link to comment Share on other sites More sharing options...
Mayolives Posted July 25, 2008 Share Posted July 25, 2008 A few days ago I had a conversation concerning this subject with Roddy at Speed Design Inc. (titaniumZ). I always respect his input concerning aerodynamics and race car fabrication in general. I ask his opinion about the effectiveness of the 2 1/2" tall roof strips that run lengthwise on the roof of car of tomorrow and more importantly, could I install roof stripes on my race car to improve aerodynamics. Apparently, NASCAR mandates these stripes because wind tunnel test would suggest they help prevent the car from flipping when turned sideways during a spin or accident. However, Roddy thought they may help to clean up the air and prevent "spill-over" which may provide more down force on the s30. So, are the drip rails a mini version of the COT's roof strips? Could they provide more stability at speed? My guess would be an added roof strip could work well on a drag race car traveling in a straight line but could possibly slow down a road course car that maneuvered lots of corners. Without wind tunnel testing, all the above is merely hot air and "guess-tamation" on my part. Quote Link to comment Share on other sites More sharing options...
WizardBlack Posted July 25, 2008 Author Share Posted July 25, 2008 A few days ago I had a conversation concerning this subject with Roddy at Speed Design Inc. (titaniumZ). I always respect his input concerning aerodynamics and race car fabrication in general. I ask his opinion about the effectiveness of the 2 1/2" tall roof strips that run lengthwise on the roof of car of tomorrow and more importantly, could I install roof stripes on my race car to improve aerodynamics. Apparently, NASCAR mandates these stripes because wind tunnel test would suggest they help prevent the car from flipping when turned sideways during a spin or accident. However, Roddy thought they may help to clean up the air and prevent "spill-over" which may provide more down force on the s30. So, are the drip rails a mini version of the COT's roof strips? Could they provide more stability at speed? My guess would be an added roof strip could work well on a drag race car traveling in a straight line but could possibly slow down a road course car that maneuvered lots of corners. Without wind tunnel testing, all the above is merely hot air and "guess-tamation" on my part. You know, my guess would be that the strips have to be vertical to get the benefit. I'd expect the roof strips on those cars do two things. 1: they act like an undertray making the air "stay in place" and run across the roof. When the car goes sideways they act like a rudder making the car slightly more prone to straighten out. 2. if the car gets completely sideways, they create quite a bit of drag to decelerate the car from above the center of gravity. Otherwise, the major deceleration force is below the CG (tires) and it is more likely that the CG will keep going past the location of this force (roll over). I've looked at the drip rails and they sure look like they are an added strip of ~2.5" wide sheet metal that is welded on. In other words, you could take 'em right off. I wonder what aero effect it would be to replace them with vertical strips (like the NASCAR stuff) in approximately the same area... Quote Link to comment Share on other sites More sharing options...
WizardBlack Posted July 25, 2008 Author Share Posted July 25, 2008 Yeh, there is no radiator or other cooling element back there? Only proper reason I can think of. The A pillar shrouds/deflectors may be effective, not sure about some of those scoops though. Nope, no radiator or anything back there. Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted July 26, 2008 Share Posted July 26, 2008 its a race car.. I would assume the rear quarter window scoops are to COOL the race driver down .. race cars do get pretty damn hot Quote Link to comment Share on other sites More sharing options...
Gollum Posted July 28, 2008 Share Posted July 28, 2008 Well, I'm not sure I'd really call just any FFR daytona couple replica a "race car", but that's certainly the emotion they're trying to evoke. I've seen several in person, there's nothing back there to be sure. Had I read this a few months ago, I could have asked brock why he designed it that way. I'm sure he would have gladly answered. But the key point I'm going to make here, is that when he had the chance to redesign the car for superperformance and give the car his update and stamp of aproval, he retained those scoops on the side. New daytona coupe from superperformance: So they obviously mean somthing. If they were for looks they'd probably be done in metal, and painted the color of the car. The fact they're clear plastic on most of these cars suggest to me that they're function over form. They're not nearly as pretty as the scoops on the GT500.... Though those scoops don't have a function. I'm kinda interested in seeing a S30 with taller metal pieces added to the drip rails. The image in my mind is pretty dorky. Quote Link to comment Share on other sites More sharing options...
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